Combat level
A player's, monster's, or non-player character's combat level indicates the difficulty in defeating him, her, or it in combat. Levels that are lower than yours display shades of green, levels that are slightly lower than one's display yellow-ish, levels that are equal to one's are displayed as yellow and levels that are higher than yours display shades of orange to red. Normally, aggressive non-player characters stop attacking you when you reach higher than double their combat level. There are exceptions, however - for example, any monsters in the wilderness will be aggressive no matter what your combat level, which is extremely annoying to player killers fighting in a multi-combat area. Monsters with a higher combat level than a player cannot be attacked by using a left mouse click. Instead, players need to right click and select the attack monster option. So, to be able to attack a Blue Dragon with combat level 111 with a simple left click, a player needs a combat level of at least 111. Calculating Combat Level Simply # Take your Prayer level and divide it by two and round down (For example, if your Prayer level is 43, dividing by two and rounding down gives you 21) # Add this to your Hitpoints and Defence levels and divide the result by 4. This is your base combat level. (For example, if your Hitpoints is 60, Defence is 70 and prayer is 43 you should end up with 37.75) # Add your Strength and Attack levels together and multiply by 0.325. Add this to your base combat level and you should have your melee combat level. # If your Magic or Ranged level is exceptionally higher than your Attack and Strength, carry on - in the calculation noted below Magic is used, but if your Ranged is exceptionally higher, use that instead in all cases # Divide your magic level by 2 and round down, and then add your magic level again to this (For example, if your magic level is 83, you should end up with 124). # Multiply this by 0.325 and add the result to your base combat level calculated above, and you should have your magic combat level. Mathematics Base = 0.25(Defence + Hitpoints + floor(Prayer/2)) Melee = 0.325(Attack + Strength) Range = 0.325(floor(Range/2) + Range) Mage = 0.325(floor(Magic/2) + Magic) Final = floor(Base + Highest of Melee, Range or Mage) Combined Formulae Melee combat level = floor( 0.25(Defence + Hits + floor(Prayer/2)) + 0.325(Attack + Strength) ) Ranged combat level = floor( 0.25(Defence + Hits + floor(Prayer/2)) + 0.325(floor(R/2) + R) ) Magic combat level = floor( 0.25(Defence + Hits + floor(Prayer/2)) + 0.325(floor(M/2) + M) ) Comments Combat level is the only in-game visible parameter that players have to evaluate another player. High combat levels do not always accurately describe a players' capabilities in other skills. There are players with maximum combat that have very low levels in other skills and there are pure skillers with no combat levels and very high non-combat skills. Yet, there is a reasonable chance that a high combat level also implies a decent skill level and a reasonable knowledge of the game. A more complicated assessment is in the trustworthiness of a player in trades. Some players place higher trust in higher combat level players, as they have more to lose when they get banned after being reported for illegal trading practices.